The Institute of Electrical and Electronics Engineers (IEEE) Standard 802.11 is a set of media access control (MAC) and physical layer (PHY) specifications for implementing wireless local area network (LAN) or wireless fidelity (Wi-Fi) communication in the 2.4, 3.6, 5, and 60 GHz frequency bands. A basic service set (BSS) provides the basic building-block of an 802.11 wireless LAN. In an infrastructure mode of 802.11, a single access point (AP) together with all associated stations (STAs) is called a BSS. A station (STA) is also sometimes referred to as a device. Thus, these two terms are interchangeable. The AP acts as a master to control the STAs within that BSS. The simplest infrastructure BSS consists of one AP and one STA.
Currently, three important market trends drive the future evolution of Wi-Fi technology towards proximity-based device-to-device networking and data exchange. The first trend is the increasing geographic density of Wi-Fi-capable devices as the Wi-Fi technology continues to penetrate the mobile and consumer electronics markets. Metcalfe's law states that the value of a telecommunications network is proportional to the square of the number of compatible communicating devices participating in that network. Therefore, a high density of Wi-Fi devices increases the utility of Wi-Fi based device-to-device networking. The second trend is the growing popularity of social networking applications, many of which are proximity based, making smartphones, tablets, and other mobile devices the natural choices as the hardware platforms for these social networking applications. The third trend is the emerging mobile health, smart home, smart building, Internet of Things (IoT), etc., which will increase data traffic among devices in the proximity.
Although the IEEE 802.11 Standards define an independent BSS (IBSS) mode wherein two or more STAs can directly communicate with each other without direct intervention from a controlling AP, the IBSS mode doesn't scale well when the number of STAs becomes large and it also restricts to a single channel data operation. The IEEE 802.11s Amendment also defines an architecture and protocol that supports the mesh network. However, an IEEE 802.11s compliant mesh network requires high power consumption due to un-synchronized beacons and significant signaling overhead during topology change, making it unsuitable for devices running on battery power or in a high density or non-stationary environment.
A neighbor awareness networking (NAN) certification program has been initiated by the Wi-Fi Alliance to provide IEEE 802.11 technology a low-power mechanism that is executed in the background of compliant devices to make the compliant devices neighbor aware. NAN, which is based on proximity, does not require the real-time connection to a Wi-Fi infrastructure, servers, GPS or other geo-location, but instead uses direct device-to-device Wi-Fi to discover and exchange information. The NAN Release 1 (NAN1) specification has been published by the Wi-Fi Alliance and enables mobile devices to efficiently discover people and services in their proximity. The Wi-Fi Alliance is currently working on NAN Release 2 (NAN2) specification by introducing many-to-many data connectivity, along with other enhancement features such as accurate ranging and privacy protection. It is envisioned that the typical applications for NAN include Wi-Fi based mobile social networking, mobile commerce, mobile advertising, wireless multi-player gaming, group chatting, etc.